Electrocardiograph of an infant with pulmonary atresia with intact ventricular septum (PA/IVS)

This ECG of a neonate demonstrates several features consistent with PA/IVS, including right atrial enlargement based on tall p waves in leads I, II, and aVF and abnormal relative left-axis deviation (QRS axis +30 degrees) due to a decrease of right-sided forces from right ventricular hypoplasia. Cyanosis in a neonate with left-axis deviation on ECG should prompt the clinician to consider PA/IVS. Although the ECG does not demonstrate significant myocardial ischemia, ST and T wave abnormalities should be ruled out on all patients with PA/IVS due to the possibility of coronary abnormalities.